Triatoma infestans is the most important vector of Chagas disease in Argentina. Experiences from Argentine national campaigns have shown indoor spraying to control triatomine bugs is both expensive and difficult. An alternative control method may be the use of pyrethroid- impregnated fabrics (PIFs), which could be both a practical and cheap complement to conventional control measures. In this study, a formulation of emulsifiable concentrate of beta-cypermethrin [a-cyano-3-phenoxybenzyl-3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropanecarboxilate] pyrethroid was used to impregnate different fabrics. The fabrics were then tested for their efficacy and persistence in killing Triatoma infestans. Insects attempting to penetrate or grasp the fabric in search of blood meals were poisoned by the exposure to the absorbed pyrethroid. Laboratory bioassays showed that the insecticidal effect of the PIFs with a dosage of 0.2 g/m² lasted longer on wool than on cotton or rayon. Eight months after impregnation, a residual efficacy of 100% was found for wool, 80% for rayon-cotton fabrics, and 50% for rayon- polyester fabrics. In addition, beta-cypermethrin-impregnated fabrics showed a better repellency effect than did fabrics impregnated with either deltamethrin or cypermethrin. For field trials, fabrics were impregnated either in the laboratory or "in situ" at a dosage of 1 g beta-cypermethrin/m² and then dried. The PIFs were placed inside homes, either under the roof or under the bed mattress. The field trials showed the PIF approach to be very effective in keeping dwellings free of triatomine bugs for at least one year and found a high degree of acceptability among the houses residents.

Asthma is the most common chronic disease among children and adolescents, and in recent decades dramatic increases in its prevalence have been reported around the world. However, previous studies have been based on a variety of methodological approaches, making it difficult to compare the results. That situation led a group of international researchers to prepare a standardized self-administered questionnaire to carry out cooperative international studies for the International Study of Asthma and Allergies in Childhood (ISAAC). During April 1996 a cross-sectional study using the ISAAC questionnaire was performed in the city of Campos Gerais, Minas Gerais, Brazil, to determine the prevalence of wheezing and other signs and symptoms related to bronchial asthma among schoolchildren. Two medical students interviewed a randomly selected sample of 200 adolescents 1314 years old registered in public schools in the city. The sample was equally distributed by sex and age. Of the schoolchildren, 28.5% (95% CI: 22.3%35.3%) had had wheezing or whistling in the chest at some point in the past. In the preceding 12 months, 6% of them (95% CI: 3.1%10.5%) had had at least one wheezing episode. A comparison of these results with ones from larger Brazilian cities studied showed that higher prevalence rates were associated with higher population densities and greater urbanization and industrialization. These results strengthen theories supporting an association between asthma and environmental factors. From this it follows that it is necessary to deal with asthma as an important public health problem in Brazil.

The epidemiology of dengue and dengue hemorrhagic fever in Santiago de Cuba, 1997 Artículos

A dengue epidemic that Cuba reported in 1997 registered more than 500 000 cases of dengue fever produced by viral serotype 1. In 1981, there was an epidemic of dengue hemorrhagic fever produced by serotype 2 of the virus. This time 344 203 clinical cases were reported, 10 312 of which were severe cases of hemorragic fever that led to 158 fatalities (101 of them among children). The reintroduction of dengue, and specifically of dengue viral serotype 2 (Jamaica genotype), was quickly detected in January 1997 through an active surveillance system with laboratory confirmation of cases in the municipality of Santiago de Cuba, in the province of the same name. The main epidemiological features of this outbreak are reported in this paper. A total of 3 012 cases were reported and serologically confirmed. These included 205 cases classified as dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), 12 of which were case fatalities (all among adults). Secondary infection with dengue virus was one of the most important risk factors for DHF/DSS. Ninety-eight percent of the DHF/DSS cases and 92% of the fatal cases had contracted a secondary infection. It was the first time dengue hemorrhagic fever was documented as a secondary infection 16 to 20 years after initial infection. Belonging to the white racial group was another important risk factor for DHF/DSS, as had been observed during the 1981 epidemic. During the most recent epidemic it was demonstrated that the so called fever alert is not useful for early detection of an epidemic. Measures taken by the countrys public health officials prevented spread of the epidemic to other municipalities plagued by Aedes aegypti.

The evolving relationship between weight-for-height and weight-for-age in children between 3 months and 6 years old receiving preschool nutritional assistance, Sorocaba, São Paulo, Brazil

The nutritional status of Brazilians has improved over the last three decades. Still, little is known about the role played by nutritional assistance programs that public institutions and philanthropic organizations provide for low-income preschool children, who face greater nutritional risk. Therefore, we carried out a quasi-experimental study to evaluate the nutritional impact of the municipal preschool nutritional assistance program in the city of Sorocaba, São Paulo, Brazil. Over the course of a year, we performed quarterly measurements of weight and height on 444 children, whose ages ranged from 3 months to 6 years. In this population, 164 children were assisted by the preschool nutritional program (intervention group), and 280 children were not (nonintervention group). The children in the nonintervention group were identified by a special census for that purpose; they did not attend the preschool but lived nearby. After obtaining informed consent and carrying out a pretest, professionals and university students interviewed the mothers of the participating children, following standard techniques and conditions. Anthropometric measurements were done by teams of two interviewers, one of whom was a permanent member of the team, using equipment calibrated by the appropriate regional technical organization. The correspondence between the first measurement and subsequent measurements was evaluated by stratifying the population into three groups by z scores for weight-for-age and for weight-for-height, using U.S. National Center for Health Statistics reference curves. The z score groupings were established at the beginning of the study for three different age groups: younger than 24 months, 24-36 months, and older than 36 months. The two study groups (intervention and nonintervention) were similar sociodemographically, with the following exceptions: maternal employment (more of the mothers of children in the intervention group had jobs outside the home); age (children in the intervention group were significantly older); nutritional status (it was worse in the intervention group); and prevalence of hospital admittance (it was higher in the intervention group). After just the first three months of the study, 32% of the children in the intervention group had moved to a higher nutritional stratum, whereas only 13% of children in the nonintervention group had shown improved nutritional status. The difference in favor of the intervention group increased with the length of the intervention and was higher among older children. These results show that the preschool nutritional assistance program helped to improve the assisted childrens nutritional status.

Vitamin A deficiency and anemia among children 12-71 months old in Honduras Articles

Vitamin A deficiency (VAD) and iron deficiency anemia (IDA) have been recognized as public health problems in Honduras for over 30 years. This paper, based on the 1996 National Micro nutrient Survey on 1 678 children 1271 months of age, presents the results for vitamin A status and anemia prevalence, as well as the level of vitamin A in sugar at the household level. The results showed that 14% of the children were subclinically vitamin A deficient (plasma retinol < 20 µg/dL) and 32% were at risk of VAD (plasma retinol 2030 µg/dL). These data indicate that VAD is a moderate public health problem in Honduras. Logistic regression analysis showed that children 1223 months old living in areas other than the rural south of the country were at greatest risk of subclinical VAD. Infection, indicated by an elevated alpha-1-acid-glycoprotein level, increased the risk of subclinical VAD more than three-fold. Children from households that obtained water from a river, stream, or lake were at twice the risk of subclinical VAD compared with other children. That same doubled risk was found for children from a household with an outside toilet. VAD can be controlled by fortifying sugar. Retinol levels in sugar at the household level were about 50% of those mandated by Honduran law. There appears to be significant leakage of unfortified sugar into the market. This is particularly true in the rural north, where 33% of samples contained no retinol. Overall, 30% of children were anemic (Hb < 11 g/dL). Logistic regression analysis showed that children whose fathers lived with them but who had not attended at least grade 4 of primary school were at 33% greater risk of being anemic. Infection and being underweight increased the risk of being anemic by 51% and 21%, respectively. Many of the anemic children had not been given iron supplements, suggesting health care providers may not be aware that anemia is widespread among young children and/or know how to diagnose it.

Growth of breast-fed and bottle-fed children up to 2 years of age: the CLACYD study, 1993-1995 Artículos

Studies done in various countries show important differences in the growth of breast-fed and bottle-fed children. In addition, it has been found that breast-fed children grow more slowly beginning at the age of 2 or 3 months in comparison with the reference pattern of the U.S. National Center for Health Statistics (NCHS) and the World Health Organization (WHO). These results cast doubt on whether maximum growth is the same as optimal growth. The objective of this study was to compare the growth in weight and length, from birth to 24 months, for a group of children who were breast-fed with that of a group who were bottle-fed. The study was also intended to describe the growth of the breast-fed group in relation to the NCHS/WHO norms and a WHO "12-month breast-fed pooled data set." For this research, data were analyzed from the "Cordoba: lactation, feeding, growth, and development" study (or CLACYD study, for its Spanish-language acronym). That study looked at a representative cohort, stratified by social class, of children born in 1993 in the city of Cordoba, Argentina. The researchers analyzed anthropometric data on 74 children who were breast-fed during the first year of life and on 108 bottle-fed children. The data had been recorded, using standardized techniques, at birth and at 6, 12, and 24 months of age. Both groups were homogenous with respect to the age and schooling of the parents, social stratum, birth order, maternal height, and childs weight and length at birth. The living conditions (housing construction and availability of water and sewer services) were better among the group that was bottle-fed (P = 0.04). The breast-fed children had a lower weight and a shorter length at 6, 12, and 24 months than did the bottle-fed children. The breast-fed children also showed a slowing in growth with respect to the NCHS/WHO guidelines beginning in the second semester. This indicates that the NCHS/WHO norms are not totally adequate for evaluating the growth of breast-fed children in Cordoba, Argentina. In the high and middle social strata, the values for the breast-fed group resembled those for the WHO "pooled data set," both in weight and length. In the low and very low social strata, weight values were satisfactory, but the figures for length were less than those of the "pooled data set." The gap in length found among the low and very low social strata does not reduce the validity of the WHO "pooled data set" reference, but rather indicates the influence of living conditions on linear growth.

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Bioethics in the context of global health programs Temas de Actualidad

This work describes the Regional Program on Bioethics of the Pan American Health Organization (PAHO)/World Health Organization (WHO), as well as the Programs main achievements. The Program was established in 1994 under a three-way agreement with the University of Chile and the Government of Chile. The Programs objective is to thematically link the work of the PAHO/WHO units and representatives in each country, in close cooperation with local public and private organizations. The Program investigates such subjects as the health of poor people, priority-setting, the growth of the private sector, salaries and incentives in the public sector, investment in hospitals, health sector reform, professional education, and working together for development. Finally, the direction and heading of the Program are presented. Its efforts are carried out as promotional, support, and service activities. These activities take the form of technical assistance for personnel training, public information dissemination, ethical situation analysis in research and services, reviewing curricula and professional practice standards, and advising on specific plans and programs.